Some ammunition, such as tank ammunition, for example, is propelled by a granular propellant which is ignited by an electrically initiated center core bayonet primer. The primer extends into the cartridge case from the base towards the projectile. However, new projectile designs protrude a significant distance into the propellant bed, limiting the length of the bayonet primer.
As bayonet primers decrease in length, the volume of propellant directly ignited by the primer decreases, thus limiting the primer's effectiveness. The effectiveness of a primer is measured in terms of both concise delay times and the absence of pressure waves in the propellant bed during combustion of the propellant. Shorter bayonet primers tend to increase delay times and pressure waves during combustion, both of which are undesirable because they can adversely affect performance.
Some projectile designs extend so far into the propellant bed that a center core bayonet design is unfeasible. A suitable substitute for the bayonet is a plurality of flexible, high burn rate transfer cords, also called burn cords. The cords can be arranged either along the wall of the cartridge case, or along the boom of the projectile, with one end connected to an electric initiator in the base. However, because the strands are flexible, they must be positioned properly in the case to be protected from the shifting forces of the propellant. Thus, there is a need for apparatus for securing a plurality of flexible burn cords in selected positions in an ammunition shell, and protecting the cords from shifting forces of the propellant in the shell.
For safety and other reasons, it is desirable to disarm ammunition for storage, shipment, and disposal without substantially disassembling it. Thus, there is also a need for transfer cord positioning and securing apparatus which allows simple removal and replacement of the electric or other combustion initiator in the base after the burn cord positioning apparatus has been loaded into a cartridge and the shell has been assembled, without further disassembly of the shell.
Accordingly, one object of this invention is to provide new and improved ignition apparatus for ammunition.
Another object is to provide new and improved positioning apparatus for strand igniter systems used in ammunition propulsion systems.
Still another object is to provide new and improved apparatus for securing a plurality of flexible burn cords in selected positions in an ammunition shell.
Yet another object is to provide new and improved apparatus for protecting flexible burn cords from the shifting forces of the propellant in am ammunition shell.
A still further object is to provide new and improved ignition apparatus for ammunition which allows removal and replacement of the combustion initiator after the ignition apparatus has been loaded into an ammunition case and the ammunition cartridge has been assembled, without further disassembly of the shell.